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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Can basin, shower & bath all share same waste? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1105443856 Message started by Ian_Reynolds on Jan 11^th, 2005, 11:44am

Title: Can basin, shower & bath all share same waste?
Post by Ian_Reynolds on Jan 11^th, 2005, 11:44am

I am fitting a new bathroom, and the sink and shower are next to each other on the internal wall (wall at the top of the stairs in an average 3 bed house). They will sit 93 inches away from the external wall housing the cast iron soil stack pipe (the wall directly opposite). I would like to run the basin waste down under the floorboards and have the shower waste tee into it. I then want the waste to tee into the bath waste and out into the stack. Is this possible? Are there any regulations on the size of piping I must use. I know there is adequate fall to cover this.

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 11^th, 2005, 12:33pm

as long as you can get a continuous run on the waste pipe there should be no trouble. Run 32mm from the basin, increasing to 40mm when the shower tees in and run 40 mm on through to the stack, taking in the bath. No problems with this set up at all.

As for the run, the regs suggest using a 1:20 fall at least, 1:40 for solids I think, but as long as you have continuous fall and you only put water down the plugholes youll be ok

Title: Re: Can basin, shower & bath all share same wa
Post by Ian_Reynolds on Jan 11^th, 2005, 1:11pm

Thanks for that.

Title: Re: Can basin, shower & bath all share same wa
Post by JerryD on Jan 11^th, 2005, 1:18pm

I've noticed a lot of the plumbers I work with use 50mm wastes where two or more outlets are combined.

There's no regulation about this but it does make sense and gives you a margin against possible problems of trap pulling or gurgling! :)

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 11^th, 2005, 1:28pm

this si true ive seen a real popularity in 2" pipe recently, but for domestic its a bit overkill imo. Was actually thinking about mentioning that but decided against. Jerry is right tho 2" is another option, if you are worried about the run it might be a bit too tight of a fit under the floor or whatever. The regs only say 1½" so go with that, 1¼" for basins. Dont know how it stands in England but up here the basin is supposed to be run horizontally for the first 500mm from the trap( although with the increase in popularity in pedestal basins this is seldom actually done)

Title: Re: Can basin, shower & bath all share same wa
Post by Ian_Reynolds on Jan 11^th, 2005, 1:47pm

Long and the short of it is that I have a sh*tty toughened glass lean-to running the width of the back of the house - and it is causing me muuuch headache. It's coming down in the spring, but in the meantime the current basin waste pipe bossing into the main stack sits above the roof of the lean-to and is really only accesable if hanging out of the toilet window. I will be able to cut it and cap it, but that's it. The bath waste on the other hand currently runs through the roof and sits inside the leanto and is more accesible.
Think I'll run 40 mm from the shower with the basin and bath teeing into it.
Nothing is ever simple..

Title: Re: Can basin, shower & bath all share same wa
Post by HandyMac on Jan 11^th, 2005, 1:57pm

The following goes without saying of course, but I'll say it anyway.

Each of the connections (basin, shower, etc) should definitely have an S-bend or P-trap. You don't want a clean air feed between you and the stack under any circumstance. Some nasty smells in there which you don't want circulating.

Also, and again it's stating the obvious, make sure your loo isn't draining into the pipework at a higher point than the other shared resources. Having pee (or worse) coming up thru your bath plughole would not be a very enjoyable experience.

HM

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 11^th, 2005, 2:05pm

wrote on Jan 11^th, 2005, 1:57pm:

If you get approved document H off the ODPM website(.pdf) it has the regs for terminating wastes to stacks with diagrams showing height of connections etc.
I'll look for the link...

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 11^th, 2005, 2:07pm

http://www.odpm.gov.uk/stellent/groups/odpm_control/documents/contentservertemplate/odpm_index.hcst?n=271&l=3

Title: Re: Can basin, shower & bath all share same wa
Post by Ian_Reynolds on Jan 11^th, 2005, 3:14pm

Top stuff. Being that I'm building an extension later in the year that link will come in very handy as the stack will be replaced along with the guttering.

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 11^th, 2005, 3:30pm

there are good links on the regs forum for building regs that will help you out too, and dont forget, we are only a click away too ;)

Title: Re: Can basin, shower & bath all share same wa
Post by jasonB on Jan 11^th, 2005, 5:01pm

If I'm doing a bathroom with a long waste run I often put an air addmittance valve at the top of the run to help prevent the water in the traps being sucked out.

Marley make one that comes with an adaptor to fit 32,40& 50mm pipe. Just make sure it is above the highest waste, usually the basin, incase of blockages.

Jason

Title: Re: Can basin, shower & bath all share same wa
Post by JerryD on Jan 11^th, 2005, 7:37pm

wrote on Jan 11^th, 2005, 1:57pm:

Each of the connections (basin, shower, etc) should definitely have an S-bend or P-trap.

I've recently had to use some of these waterless traps, just a straight 'trap' but it has a rubber tube internally where the waste water flows. The rubber is made so that it 'shuts' together when no water is passing through, thus forming a seal against sewer smells.

These are useful in bathrooms or cloakroom which are only used occasionally as the trap can't evaporate.

Title: Re: Can basin, shower & bath all share same wa
Post by Ian_Reynolds on Jan 12^th, 2005, 10:43am

Blimey - it's like aladdins cave in here. That is exactly what I was looking for for my kitchen as my sink waste is bossed into the main stack and the local residents seem to hold a secret monthly 'throw a decaying carcus into the sewer' competition once a month, which consequently, despite a fully functional p trap under the sink, makes my kitchen stinks like a gents.
Is there any particular way in which that device needs to be fitted?

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 12^th, 2005, 11:25am

wrote on Jan 12^th, 2005, 10:43am:

Sounds like your trap is being sucked out, you could put an in-line trap in the run(although the trap Jerry describes looks like its in-line or maybe pedestal type) Lots of things can suck out a trap seal, wind blowing across the stack, discharge from other appliances etc. I'd find the cause of the broken seal(and make sure its not the missus pouring fat/spaghetti etc down it!) Those strainer things for sinks are great to stop all that sh*t going down the plug, as it rots in the bottom of the trap it stinks!!!
Also, check your sink overflow for remnants of gunk as that can also cause a stink, so to speak.

ßtk

Title: Re: Can basin, shower & bath all share same wa
Post by Ian_Reynolds on Jan 12^th, 2005, 12:17pm

Finally, I was thinking of opting for Anti-vac traps in bath, basin and kitchen sink. Are these generally ok, and would I have the same problem?

Title: Re: Can basin, shower & bath all share same wa
Post by billythekid on Jan 12^th, 2005, 12:40pm

anti-vac traps are a good idea, should have mentioned them in my last post. ;D